METAL SEQUESTERING BY MICROORGANISMS IN AND FROM AQUATIC ENVIRONMENTS

本提案是对#年所做工作的扩大 1992-93财年，题为《微量金属的调查》 微微浮游生物中多聚磷酸盐的隔离作用。 关于吸收痕量和重金属的各种机制和 在自然界中发现的固定在微生物联盟中的 水生环境。我们的方法将是使用变速器 电子显微镜与X射线能谱分析相结合 (EDX)，研究细菌大小的细胞及其相关的非细胞 微粒。这种定性和半定量的方法将使 美国分析细胞和细胞成分的元素含量，以及 使我们有可能定位金属离子成为 集中精力。我们过去一年的学习作为培训是卓有成效的 因为我们现在正在进行更复杂的天然水生生物的检查 系统。我们将尝试分离出更多具有重要数值意义的 金属固定化物种，并研究它们吸收金属的倾向。 我们将检查金属污染的水上沉积物中的细菌和 伴生颗粒物、重要的含重金属活性污泥 并尝试将积累的金属定位在组成电池的电池内或电池上 生物质。吸收和浓缩一种重金属的纯文化 在相关机制的研究中具有巨大的潜在价值，但它们也 可能被开发用于水净化、贵金属等方面 回收或其他实际用途。更重要的是来自一个 从环境的角度来看，重金属是可以被追踪的 使用EM-edX系统将沉淀物转化为细菌细胞团。许多 也可以作为食草性原生动物的食物供应 其他无脊椎动物。我们在目前的提案中所作的努力将 为这类研究奠定了基础。

The present proposal represents an expanded effort of that undertaken in the 1992-93 FY, which was entitled "Investigation of trace metal sequestering by polyphosphate bodies in picoplankton." We will now focus on the various mechanisms by which trace and heavy metals are taken up and immobilized within the microbial consortium that are found in the natural aquatic environments. Our approach will be to employ the transmission electron microscope in conjunction with X-ray energy dispersive analysis (EDX), to study bacterial-sized cells and their associated non-cellular particulates. This qualitative and semi-quantitative approach will enable us to analyze cells and cell constituents for their elemental content, and make it possible for us to localize regions in which metal ions become concentrated. Our study over the past year has been fruitful as training ground as we now undertake examination of more complex natural aquatic systems. We will attempt to isolate additional numerically important, metal immobilizing species and study their propensity for metal uptake. We will examine metal polluted aquatic sediments for bacteria and associated particulates, important heavy metal bearing activated sludge and attempt to localize accumulated metals in or on cells making up the biomass. Pure cultures that take up and concentrate a heavy metal have great potential value in the study of mechanisms involved but they also may be developed for use in aspects of water purification, valuable metal recovery or other practical uses. Of greater importance from an environmental standpoint is the fact that a heavy metal can be tracked from a sediment into a bacterial cell mass using the EM-EDX system. Many of the bacteria can also serve as a food supply for grazing protozoa and other invertebrate animals. Our effort in the present proposal will lay a groundwork for these kinds of studies.